The present invention relates to industrial air filter and like doors with standard handle-dog actuation and more particularly to a much improved handle-dog actuation assembly and system.
Industrial air filter doors, marine bulkhead doors, and like doors are required to be air tight, water tight, or tight with respect to both air and water. It will be appreciated that reference to air and water are illustrative of fluids, vapors and liquid, from which a variety of doors must provide effective sealing. In nuclear power plant confines, for example, air filter doors are part of the containment system and, thus, must provide a predetermined effective seal with respect to the passage of air and gases through the opening to which they provide closure. Similar requirements are placed upon marine bulkhead doors which must be water tight for obvious reasons. It will be appreciated that other industrial environments similarly require door and closure systems which are leak-proof, yet are easy to access for maintenance, servicing, and like needs.
In the industrial air filter door environment, it often is necessary to provide access through the door for servicing air filters, for example. Nuclear power plants, for example, may contain literally hundreds of these air filter doors which are required to meet certain minimum governmental specifications. Unfortunately, the typical maintenance worker who accesses these doors often does not exercise the requisite degree of care required for maintaining the integrity of the door seal and door closure mechanisms. Often, the handles become rusted (oxidized), exhibit a lack of lubrication, are painted and re-painted, or otherwise become quite difficult to actuate. Often, the worker will employ a length of pipe or a wrench for providing increased leverage for actuating the closure mechanism. Damage to the mechanism often results.
Another problem often encountered is to figure out which way to rotate the handle in order to unlock the door. While this may seem an elementary problem, it should be understood that each door often will have six or more closure mechanisms which quite frequently do not rotate in the same direction for opening and closing each of the mechanisms. This uncertainty as to which direction to rotate the handle is exacerbated when coupled with the frequent rusting and lack of lubrication which is encountered. Often, the worker will struggle mightily with a length of pipe for rotating the handle only to discover later that he was forcing the handle in the wrong direction. No indicia on the outside of the door is correlative with the position of the handle, i.e. whether the mechanism is in an open or a closed position.
Another problem frequently encountered is that the seal about the door becomes damaged due to the dog or handle being forced against the seal. This can happen because frequently the closure mechanism is so loose that it will not stay in a given position. This means that gravity forces the handle to be in a downward position. If the downward position of the handle translates into a closed position of the mechanism, the handle must be held in an upwardly-disposed position in order for the door to be opened. With a six foot door having six or more of such loose mechanisms, it will be appreciated that a worker working alone has a great deal of difficulty in opening or closing the door since he has but two hands. In forcing the door shut under such circumstances, often the dog or handle scrapes across the seal, thus destroying its integrity and the integrity of the door for its intended purposes.
Prior proposals aimed at providing air tight or water tight doors include U.S. Pat. Nos. 2,440,764, 2,156,635, 2,335,450, 1,468,081, 1,064,278, and 2,295,324. The ultimate listed patent provides a complex and expensive closure actuating and locking mechanism which operates by a single handle on the outside of the door. While such door may find favor in submarines, its complexity and cost make it prohibitive in most industrial and marine applications.
Thus, it will be observed that a simple, yet reliable industrial door with actuation assembly is required. The present invention addresses this long felt need in industry.